Why spend money on expensive energy bars when you can make this easy low carb protein bar recipe with only 5 simple ingredients? These peanut butter protein bars are chewy and fudgy yet they stay firm at room temperature. The recipe is sugar free, low carb, gluten free and Keto.
Shop-bought low carb protein bars
I get it. Shop-bought low carb protein bars are suuper convenient. But they often come with a hefty price tag. Plus, many contain additives to extend shelf life, questionable sweeteners and inflammatory vegetable oils. And while they do solve an immediate problem (=hunger), I've never sampled one that actually tastes GREAT.
Easy Keto protein bar recipe
With a teeny-tiny bit of planning ahead, you can make absolutely DELICIOUS FUDGY, CHEWY peanut butter protein bars at home. They'll boost your energy after a workout and they're a fat-fuelled, protein-rich snack if you simply need a pick-me-up in between meals.
The main ingredient of this healthy Keto protein bar recipe is peanut butter. Peanut butter already has a high protein content, which I'm boosting with additional protein powder. I never add protein powder to my smoothies (I prefer straight-low carb granola, up veggie smoothies such as this detox Keto green smoothie). But I do like to add a scoop to my granolas because it helps to add extra crunch - check out this the crispy clusters are to die for.)
I experimented quite a bit with this recipe, because originally I wanted to create a no-bake protein bar. The problem with this was that no mix was sufficiently firm at room temperature whilst still fudgy and chewy. I did not want to coat the whole bar in chocolate only to get around that issue.
The solution? 25 minutes in the oven. Yes, a lil' bit of baking produces absolutely awesomely healthy protein bars that you can carry around all day in your handbag until hunger strikes!
How to make low carb peanut butter protein bars - step by step:Â
1.) Put the ingredients for the base and the top layer in separate bowls. I decided to use a brown sugar alternative to sweeten, but any granulated erythritol will work.
Your peanut butter should be EASY TO SCOOP. Give it a good stir if necessary - especially in larger pots it tends to settle on the bottom.
2.) Mix your ingredients with a fork and knead with your hands until you have a smooth dough.
3.) Grab yourself an oven-safe container. The mixture will fill a space of 5 x 6 inches. Your dish is larger than that? No problem. Simply fold a bit of aluminium paper and use it as a separator. That way, you can use only part of your casserole dish. The mixture does not spread.
Line the space with parchment paper and fill in first the peanut layer, then the chocolate peanut layer. Or do it the other way around 🙂
4.) After 25 minutes of oven time the bars are ready. This is what you should look out for: The top does not glisten any more. It has set and the edges are beginning to brown.
Wait until your low carb protein bars have cooled down before you cut them. They will be fragile and soft while hot, but firm up as they cool down.
Healthy peanut butter protein bar ingredients
There are plenty of peanut butter protein bars out there that use oats to thicken. I chose coconut flour because not only is it low carb and magnificently healthy, but it also absorbs plenty of liquid. Together with the protein powder, it is the ideal binder.
You can use crunchy or smooth peanut butter in this recipe, whichever you prefer. The bars with crunchy peanut butter can crumble a little when you cut them. If you are after razor-sharp edges, I recommend you use smooth peanut butter.
Always check the label when buying peanut butter to make sure it does not contain added sugar! I like to use the Meridian brand here in the UK - it contains 100% peanuts and nothing else.
You can add 1 teaspoon of cinnamon for a taste variation or a pinch of salt. If you're feeling a bit naughty, you could also add a handful of sugar free chocolate chips!Â
How long do homemade sugar free protein bars last in the fridge?Â
Your peanut butter bars will keep on the kitchen counter for a couple of days and a good 7 days in the fridge. You can also freeze them. What I love about them is that you can transport them easily. They are a perfect on-the-go snack.
Love peanut butter? Check out these recipes:Â
- Keto Chocolate Peanut Butter Fudge (Sugar Free Fudge)
- Low Carb Peanut Butter Cookies Recipe (Flourless)
- Grain Free Peanut Butter Granola (Sugar Free)
- Keto Peanut Butter Chocolate Bars
Tried these peanut butter protein bars? Give them a star rating below!
★ STAY IN TOUCH on FACEBOOK, PINTEREST and INSTAGRAM  for more great food and join my NEWSLETTER for the latest updates and a FREE EBOOK.★ Â
Recipe

Peanut Butter Protein Bars
from Sugar Free LondonerNote: The servings slider only changes the first amount in each line and not any subsequent amounts. Please make your own calculations where necessary.
Ingredients
Base Layer
- ½ cup / 130g peanut butter unsweetened
- 1 ½ tablespoon coconut flour
- 1 tablespoon protein powder
- 1 ½ tablespoon granulated erythritol
Top Layer
- ½ cup / 130g peanut butter
- 1 tablespoon cocoa powder unsweetened
- 1 ½ tablespoon granulated erythritol
- 1 tablespoon protein powder
- 1 ½ tbsp coconut flour
Instructions
- Preheat the oven to 175 Celsius / 350 Fahrenheit.
- Put the ingredients for the base and the top layer in separate bowls and mix with a fork, then knead with your hands to combine.
- Line a ovenproof dish with parchment paper. Spread the base layer, then add the top layer to fit a space of ca 5 x 6 inches.
- Bake for up to 25 minutes. The bars are ready when the top has set and is beginning to brown around the edges. Remove and let cool to room temperature before cutting.
Notes
Nutrition
This post contains affiliate links. If you click on one of these links and purchase a product, I may earn a small commission, at no extra cost to you. Thank you for supporting Sugar Free Londoner.
Mary
I prefer no chocolate so can I just double the base layer to make them?
Katrin Nürnberger
Of course!
Mary
Would it be possible to use peanut butter powder to reduce the fat?
Katrin Nürnberger
I don't think so because they'd just be dry and brittle.
Mary
I meant if I reconstituted the peanut powder to with water per instructions? Are coconut flour and almond flour interchangeable?
Thanks
Katrin Nürnberger
As a rule of thumb, you'll need to use about 3 x more almond flour than coconut flour. It is less absorbent. As for the peanut powder, you'd have to try it out and see whether it works. I have never used it. But since you'd be replacing fat with water, my guess is that the bars may turn out dry.
aidan
Hi, I'm new to keto so only learning. After reading the nutrition info do these bars work out roughly 40g each and 2 net carbs?
thank you
Aidan
Katrin Nürnberger
Hi Aidan, yes, these bars are 2g net carbs per bar. I did not weigh them.
aidan
Sorry Katrin, I thought I saw somewhere they were 40g each. I just made them but rather than make in a tray I used little cup cases to make individual portions. I always find that peanut butter no matter the brand is always a little bit clawing and coats the mouth and makes things dry at times. I found these to be a little dry (maybe under baked as took them out after 20 mins) but very very tasty. I love lots of things with peanut butter and these were delicious and will definitely be making them again. I also topped a couple with a little chocolate and god help me I could 3 or 4 at a time lol...Thank you
HEATHER VIRGINIA PETERSEN
pretty good and very easy to make!
Susan
What about powdered stevia? I'm type 1 diabetic so powdered stevia works best for me but confused on the conversion. Ty in advance!
Katrin Nürnberger
Hi Susan, you can use any sweetener as long as it is a 1:1 sugar substitute. It should say on the pack. I've had a few powdered stevia brands that are twice as sweet as sugar, so be sure you're not using too much.
Susan
Thank you!
Susan
What would the substitute be if I use almond flour instead?
Katrin Nürnberger
Use 3x more almond flour than coconut flour.
Damian
Hi, for the base recipes said granulated erythritol, is necessary grind it or not? I wish to do this bars asap, thank you.
Katrin Nürnberger
It's not necessary to grind it. But you can use powdered sweetener if you prefer. Both work just as well. I used a brown sugar alternative that is granulated.
Diana
Can I assume that the sugar listed is actually sugar alcohols since you are not using any added sugars? Thank you!
Katrin Nürnberger
No, I actually don't include the sugar alcohols at all because they are not processed by our bodies, making them essentially zero carb. The sugars you're seeing are from the other ingredients. Most foods contain some sugars from carbs.